1. Field of the Invention
The present invention relates to a field of vehicle testing technique, particularly to a 3D single-point clamp of four-wheel aligner for vehicles and a method of using the same.
2. Description of the Related Art
The trade of domestic automobile maintenance and repair equipment develops rapidly in recent years and gradually becomes a leading enterprise among some trades. Some people with breadth of vision focus on the foreign market and develop the business in overseas markets by cooperating with agents or setting representative offices. Consequently, such tendency in accordance with the position of China in the world economic state is formed and becomes the major growing way of fast development of automobile repair trade in the future. Due to the progressive development of the vehicle market in China, the prospects of after-sales service of vehicle in China are also focused attentively, which benefits the automobile repair market greatly. Because the ratio of household car purchases is increased, and the consciousness of the vehicle owner to the vehicle maintenance and repair is more intensive, more and more demand of vehicle detection, maintenance and repair equipment for domestic vehicles is needed.
However, the present techniques of domestic maintenance and repair equipment fall far behind the nationwide rivals, and the domestic technique mainly imitates the foreign techniques. The four-wheel aligner is one of major products among the automobile maintenance and repair equipment and has a big demand of the market, a product technique with high difficulty, and a high added value. As the nation subjects the traffic security to an increased attention and stipulations of management, the market demand of four-wheel aligners will rapidly expand under the guidance of the national policies.
The common detecting methods of four-wheel aligners in the present market mainly comprises: laser, PSD, CCD, and 3D; the characteristics thereof are as follows:
1. Laser:
Laser is a new light source which is used as a light source for system measurement and is applied to the four-wheel aligner. Laser is exported by vertical straight lines, which causes a narrower measuring range determining the speed of the laser products, has zero compensation, and needs to calculate the thrust line manually. As a result, the accuracy of measurement is low and the detecting speed is slow. Because of the light spots and the scales, the artificial error is existed, and the laser is apt to be interfered by the outer environment. Accordingly, it is not ideal to apply the laser as a light source to the four-wheel aligner.
The laser is known as the affair which has the certain harm to the vision of human, so the security certification, e.g. UL, CE and so on, is not easily granted. The laser has been eliminated in Europe, America, and Japan; however, it is still used in some countries, such as China and part of Southeast Asia nations.
2. PSD:
PSD is also called “Position Sensitive Detectors”. As everyone known, PSD is not used in four-wheel aligners in almost all the foreign countries. It is only used greatly in the machinery of Korea. The working principle of PSD is that while a position of a light receiving face of the PSD surface is illuminated, the output current changes correspondingly to obtain an illumination location. PSD is a component of simulation for DC/AC conversion having the circumstance of losing data. Although some special techniques can be used to avoid the drawbacks to a certain extent, the PSD can only measure a single light source in principle. The PSD can only be used in the industrial environment, namely, the temperature of the PSD drifts seriously and the PSD is apt to be affected by the light of the environment. The changes of temperature make the output zero position vary in a range of tens of millivolts, and the influence of light makes the value captured by the system become unstable. With the two drawbacks, the PSD loses the measuring accuracy and the stability of equipment. The inaccuracy and the poor repetition degree are the most serious defects of the PSD.
3. CCD:
CCD, a semiconductor digital device which is also called “charge coupled device”, is divided into a linear CCD and an area CCD. The CCD is anew semiconductor-integrated photoelectric device developed in early seventieth of the twentieth century. Thousands of respective photosensitive units are gathered on a silicon surface. While the light illuminates on the photosensitive surface, the photosensitive units illuminated by lights gather the photoelectrons and output the light quantity by shifting to generate the information of the light position and the light intensity. As a result, the COD provides the characteristics of obtaining high measuring accuracy within 0.05 degrees, having no temperature coefficient, and attaining a long duration of the use.
The use of CCD can obtain a preferable adaptability of the environment. Other techniques have a variety of restrictions in use, for instance, they cannot be used in some environments, such as at the place with complicated lights, in a magnetic field with the powerful electricity, and in a room with a great variation of temperature. The above environments belong to typical environments of the ordinary automobile repair workshop. The requirement which forbids the open of doors and windows, has different measurement data between the cool morning and the hot noon, and forbids a big electric machinery to be set nearby is too over for the four-wheel aligners. Consequently, the four-wheel aligners produced by Europe and America adopt the CCD technique, for instance, TANK, BEISSBARTH, and ARES, which are enough to illustrate the advantages of the CCD products.
4. 3D:
The measuring method of 3D is to use the technique of graphic identification which is executed by collecting graphic data on the reflecting board disposed on the wheel by a CCD digital camera to measure the relative accuracy of the wheel and pushing the wheels backwards and forwards manually to allow the head of the CCD to collect the data and find out the coordinate and the angle of the wheel. This is a considerably progressive measuring method and is used commonly in Europe and America. However, such method does not strictly limit the machinery accuracy of elevators and rotating plates. This method obtains an easy use and a high detecting accuracy, so the application of 3D becomes a mainstream in the market.
Likewise, 3D scanning is an innovative technique which combines the light, machinery, electricity, and computer integrally for scanning the spaces, shapes, structures, and colors of the object in order to obtain a space coordinate of the surface of the object. The main purpose of 3D is to convert the three-dimensional data of the object into the digital signals which can be directly processed by the computer, thereby providing a considerably convenient and rapid technique for the digitization of the solid object.
The 3D canning technique carries out the non-contact measurement and provides the fast speed and high accuracy. The measuring results can be directly associated with various software interfaces. Consequently, the 3D scanning technique becomes popular among the application of CAD, CAM, and CIMS. In manufacturing trades of developed countries, the 3D scanner is used as rapid three-dimensional measuring equipment because of its rapid speed of measurement, high accuracy, non-contact feature, and convenient use, so the 3D scanner has more and more applications. The 3D scanner is used to scan the hand boards, samples, and models to obtain the 3D dimension data, and these data can be directly associated with the interfaces of CAD and CAM, whereby the CAD system adjusts and repairs the data and then sends the date to the processing center or fast shaping equipment for manufacturing. Therefore, the cycle of manufacturing products can be greatly shortened.
The worldwide equipment mostly uses the machinery with XY axes as a rule to measure or applies a high-grade automobile producing dynamic laser to measure. The procedures of the aforementioned methods are complicated and have high manufacturing costs, which is not suitable for the development of popularizing automobiles.
Recently, the common clamps associated with the 3D techniques of four-wheel aligner worldwide are used to clamp the target of graphic for measuring are described as follows:
A: multi-point pin-shaped clamp: in the quick clamp of BMW 175-348-1 and is also used in the quick clamp of 175-541-1, a pin which is 120 millimeters long is applied to some special and deep wheel rims and wheel hubs with retracting holes. The clamp is mainly suitable for high-class vehicles, for example, BMW and Mercedes-BENZ. In the field of four-wheel aligner, some special models of vehicles need the assistance of special clamps to finish the measurement of the four-wheel aligner, such as Mercedes-BENZ and BMW in German vehicles brands. The clamp used in these two vehicles needs to cooperate with the originally manufactured wheel rim. The wheel rims of Mercedes-BENZ and BMW are designed to define measuring holes beside the fixing screws for allowing the special clamp to insert into the holes and position and using the grip to fix the clamp on the rim. This method makes the axis of the four-wheel aligning sensor and the axis of wheel hub overlap and accurately measures the front angle and the outward inclined angle by having the horizontal surface and the vertical surface to more close attached to the actual situation of the wheels. By the aforementioned method, the program of eccentricity compensation can be omitted to increase the efficiency. As it should be, the specific measuring procedures and measuring tools are needed at the same time. For example, Mercedes-BENZ needs the measuring tools of ROMESS and the expanding tools of front angle. Haekeye Elite of HUNTER is an object which combines the clamp and the reflecting board of the conventional 3D aligner for being installed on surface of any rim of wheels. It has a width to be set at one third of the conventional 3D aligner and is amended into a surface contact to replace three-point or four-point contact of the conventional aligner; consequently, the efficiency is much higher while clamping, and the effect of “universal clamp” is conducted in the surfaces of wheel hubs with varied shapes.
B: Three-point clamp: The shape of the clamp is similar to a Y shape, and the material of its three points is hard plastic. The quick aligning clamp completes the action by using a positioning pin and a clamping arm. During the installation of the clamp, the wear of the clamp should be decreased possibly. By the change of the size of the circle defined by the three points, the clamp can be adapted to wheels with varied specifications. According to the marked size of the wheels, the user has to adjust two grips which are in the lower positions, lodge them in the border of the rim, move and fasten the grips on the top to the wheel tire edge by a heart-shaped shaft, put an adjustable clamping arm on the wheel, press down the fastening levers at two sides toward the direction of the wheel forcibly, move the clamping arm to the tire tread, and then make sure that the two ends are well adjusted before loosening the clamping arm.
C. Four-point clamp: This clamp is used in the wheels made of steel aluminum alloy of which the size is set from 10″ to 28″. The slide of the clamping arm can be automatically leveled at the middle, and the needed size is obtained by rotating the star nut tightly. The gripping grip and the pressure piece with rubber pad allow the clamp to be installed on all wheels, including alloyed wheels with irregular shapes. While using, the eccentricity compensation of the wheel rim must be executed, whereby it can adapt to all wheels.
The four-point clamp as shown in FIG. 1 is a present technique which is a target clamp 2′ for installing the target board. The circumference of the target clamp 2′ is supported against the interior edge of the wheel tire 1′. The target board is installed on the target clamp 2′. The target clamp 2′ can be slightly adjusted for adjusting the target board at the center of the tire 1′. However, the present target clamp 2 has a complicated installation, a big volume, heavy weight, and high repairing costs, so the procedure for adjusting the target board is complex and difficult.
Accordingly, the inventor of the present invention provides a single-point clamp of 3D vehicle four-wheel aligner (hereinafter referred to as “vehicle four-wheel aligner”) and a using method thereof.